Fig. REF  compares two simulation models, Run-\(\xi \) 20 and Run-\(\xi \) 100,
both with the same phase transition timescale \(\Delta t=10\, \rm kyr\) , but different
density flattening degrees towards the equator \(p\)  and density equator-to-pole
ratios \(\xi \) , namely, \(p=1/4\)  and \(\xi =20\)  (Run-\(\xi \) 20) and \(p=3/4\)  and \(\xi =100\) 
(Run-\(\xi \) 100), respectively.
The different pre-Wolf-Rayet morphologies of the circumstellar medium profoundly impact the
development of the shell generated by wind-wind interaction between blue supergiant
to the Wolf-Rayet winds.
The denser the material in the equator, the more collimated the Wolf-Rayet stellar
wind (Fig. REF b), as a result of the thicker disc-like blue
supergiant distribution (Fig. REF a). On the other hand,
the simulation with a thinner equatorial plane produces a peanut-like nebula,
recalling the mechanisms for the shaping of the homunculus of
\(\eta \) -Carina [1]}, [2]}, [3]}.
Note the gradual opening of the magnetic field lines as the wind speed
accelerates (Fig. REF a-e,b-f).
Again, this is mostly shaped by the blue supergiant wind whose velocity
gradually increases during the phase transition up to reaching the fast
values of the Wolf-Rayet star (black dotted line in Fig. REF c,d).
The discrepancy between peanut-like and jet-like Wolf-Rayet nebulae persists at later times,
when the stellar phase transition keeps going (Fig. REF e,f).
